1. Field of the Invention
The present invention relates to recovering and reusing, while applying resist composition onto silicon wafers to form thin films thereon, the resist composition scattered from spinner and no longer usable on the silicon wafer.
More particularly, this invention relates to a process and apparatus for recovering the scattered unused resist composition as mentioned above for reuse.
2. Discussion of the Prior Art
Resist compositions are used in large volumes, for example, in semiconductor industries or in printing industries. For example, resist compositions are used to manufacture integrated circuits, e.g. by the spin-coating technique whereby they are applied, by means of a spinner or the like, to silicon wafers to form thin films. With this technique of coating silicon wafers, however, more than 90% of the resist composition used is scattered without being coated on silicon wafers, resulting in waste liquid having no use. As a matter of fact, the waste liquid is collected and commissioned to industrial waste disposal workers for disposal.
From the standpoint of efficient utilization of resources, the inventors have made extensive studies on a process and an apparatus for recovering for reuse such resist compositions otherwise disposed of as waste liquid, and succeeded in providing a process for recovering for reuse such resist composition waste liquid as mentioned above as well as an apparatus therefor.